Azure Question posted in
The official documentation to get you started can be found here.

Setting loglevel for Azure Function using Environment variable

I’m trying to control the log level for my C# Azure Function. The goal is to change the log level without having to redeploy the function. The idea is to change the Environment variables in order to achieve this.

I added an environment variable to control the log level:

Environment variable

It doesn’t seem to work, as I’m still seeing Debug and Information logging:

App Insights logs

My host.json looks like this:

{
    "version": "2.0",
    "logging": {
      "applicationInsights": {
        "samplingSettings": {
          "isEnabled": true,
          "excludedTypes": "Request"
        },
        "enableLiveMetricsFilters": true
      },
      "logLevel": {
        "default": "Debug"
      }
    }
}

And Program.cs like this:

var host = new HostBuilder()
    .ConfigureFunctionsWebApplication()
    .ConfigureLogging(builder => builder.SetMinimumLevel(LogLevel.Debug))
    .ConfigureServices(services =>
    {
        services.AddApplicationInsightsTelemetryWorkerService();
        services.ConfigureFunctionsApplicationInsights();
        services.Configure<LoggerFilterOptions>(options => options.Rules.Clear());      
    })
    .Build();

host.Run();

When i run my function app locally it works as intended when i change my local.settings.json:

{
  "IsEncrypted": false,
  "Values": {
    "AzureWebJobsStorage": "UseDevelopmentStorage=true",
    "FUNCTIONS_WORKER_RUNTIME": "dotnet-isolated",
    "AzureFunctionsJobHost__logging__LogLevel__default": "Warning"
  }
}

My function:

 public class Function1
 {
     private readonly ILogger<Function1> _logger;

     public Function1(ILogger<Function1> logger)
     {
         _logger = logger;
     }
     
     [Function("LogDebug")]
     public IActionResult RunDebug([HttpTrigger(AuthorizationLevel.Function, "get", "post")] HttpRequest req)
     {
         _logger.LogDebug("***********DEBUG***********");
         return new OkObjectResult("Welcome to Azure Functions!");
     }
     
     [Function("LogInformation")]
     public IActionResult RunInformation([HttpTrigger(AuthorizationLevel.Function, "get", "post")] HttpRequest req)
     {
         _logger.LogInformation("***********INFORMATION***********");
         return new OkObjectResult("Welcome to Azure Functions!");
     }

     [Function("LogWarning")]
     public IActionResult RunWarning([HttpTrigger(AuthorizationLevel.Function, "get", "post")] HttpRequest req)
     {
         _logger.LogWarning("***********WARNING***********");
         return new OkObjectResult("Welcome to Azure Functions!");
     }
 }

Can someone shed some light on what I’m missing? Thanks in advance.

Tags:

2

Answers


  1. Chosen as BEST ANSWER
    0

    With some help from a colleague I found a way to control the log level with the environment variables.

    I changed Program.cs to the following:

    var host = new HostBuilder()
    .ConfigureAppConfiguration((context, config) =>
    {
        config.AddJsonFile("host.json", optional: true);
    })
    .ConfigureFunctionsWebApplication()
    .ConfigureServices((_, services) =>
    {
        services.AddApplicationInsightsTelemetryWorkerService();
        services.ConfigureFunctionsApplicationInsights();
        services.Configure<LoggerFilterOptions>(options => options.Rules.Clear());
    })
    .ConfigureLogging((context, logging) =>
    {
    logging.AddConfiguration(context.Configuration.GetSection("AzureFunctionsWorker:Logging"));
    })
    .Build();

host.Run();

    This change allows logging to be configured by the environment variables.

    My host.json looks like this:

    {
  "version": "2.0",
  "logging": {
    "console": {
      "isEnabled": true
    },
    "applicationInsights": {
      "samplingSettings": {
        "isEnabled": false,
        "excludedTypes": "Request"
      },
      "enableLiveMetrics": true,
      "enableDependencyTracking": true,
      "enablePerformanceCountersCollection": true
    },
    "logLevel": {
      "default": "Error"
    }
  }
}

    I can set my environment variables according to the desired log level: Environment variables

    And the result looks like this: Azure portal logs


  2. 0 
     .ConfigureLogging(builder => builder.SetMinimumLevel(LogLevel.Debug))

    you have set minimum level to Debug. This code with minimum level Debug is overriding for application insights. Its working fine locally but for portal its overriding.

    host.json:

     {
    "version": "2.0",
    "logging": {
      "applicationInsights": {
        "samplingSettings": {
          "isEnabled": true,
          "excludedTypes": "Request"
        },
        "enableLiveMetricsFilters": true
      },
      "logLevel": {
        "default": "Debug"
      }
    }
}

    Function.cs:

    using Microsoft.AspNetCore.Http;
using Microsoft.AspNetCore.Mvc;
using Microsoft.Azure.Functions.Worker;
using Microsoft.Extensions.Logging;
using System.ComponentModel;

namespace FunctionApp5
{
    public class Function
    {
        private readonly ILogger<Function> _logger;

        public Function(ILogger<Function> logger)
        {
            _logger = logger;
        }

        [Function("Function")]
        public IActionResult Run([HttpTrigger(AuthorizationLevel.Anonymous, "get", "post")] HttpRequest req)
        {
            _logger.LogDebug("************DEBUG***********");
            _logger.LogInformation("*************INFORMATION*************");
            _logger.LogWarning("******************WARNING**************");
            _logger.LogError("************ERROR***********");
            _logger.LogCritical("************CRITICAL***********");
            _logger.LogInformation("C# HTTP trigger function processed a request.");
            return new OkObjectResult("Welcome to Azure Functions!");
        }
    }
}

    I deployed code with same and I was also getting all level logs in Application insight. but in LogStream I was getting above Warning level.

    Program.cs:

    using Microsoft.Azure.Functions.Worker;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Hosting;
using Microsoft.Extensions.Logging;

var host = new HostBuilder()
    .ConfigureFunctionsWebApplication()
    .ConfigureLogging(builder => builder.SetMinimumLevel(LogLevel.Debug))
    .ConfigureServices(services =>
    {
        services.AddApplicationInsightsTelemetryWorkerService();
        services.ConfigureFunctionsApplicationInsights();
        services.Configure<LoggerFilterOptions>(options=>options.Rules.Clear());
    })
    .Build();

host.Run();

    you need to set minimum level to Warning. I am able to see in both places in application Insights and Log Stream both

    Program.cs:

    using Microsoft.Azure.Functions.Worker;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Hosting;
using Microsoft.Extensions.Logging;

var host = new HostBuilder()
    .ConfigureFunctionsWebApplication()
    .ConfigureLogging(builder => builder.SetMinimumLevel(LogLevel.Warning))
    .ConfigureServices(services =>
    {
        services.AddApplicationInsightsTelemetryWorkerService();
        services.ConfigureFunctionsApplicationInsights();
        services.Configure<LoggerFilterOptions>(options=>options.Rules.Clear());
    })
    .Build();

host.Run();

    Login or Signup to reply.
Please signup or login to give your own answer.

Back To Top
Search